Beverage preparation machines are well-known in the food industry and consumer goods domain. Such machines allow a consumer to prepare a single serving of a beverage such as brewed coffee, espresso coffee, tea, hot chocolate drink, or the like on command.
Most beverage preparation machines for in-home use operate according to a system in which beverage ingredients are provided as individually-packaged, single-serving portions. Such portions can be soft pods, pads, or sachets, but increasingly more systems use semi-rigid or rigid portions such as rigid pods or capsules. In the following, it should be understood that the beverage machine in question is a beverage preparation machine working with a rigid or semi-rigid capsule.
In many instances, the capsules for use in beverage preparation machines are sealed. Such sealed capsules are advantageous in that they protect the ingredient contained therein from the surrounding atmosphere, improving the shelf life of the capsule. Typically, such closed capsules are made from gas- and/or moisture-impermeable material, and feature a rigid or semi-rigid body having one of its walls made from a membrane which is breached during the beverage preparation process.
The beverage machine preferably comprises a receptacle for accommodating said capsule, and a fluid injection system for injecting a fluid, preferably water, under pressure into said capsule. In most applications, the water injected into the capsule under pressure is heated, generally to a temperature above 70° C. and preferably between 80° and 90° C. However, in some particular instances it may be advantageous to inject tepid or chilled water. The pressure inside the capsule chamber during extraction and/or dissolution of the capsule contents is typically about 1 to about 8 bar for dissolution products and about 2 to about 12 bar for extraction of roast and ground coffee.
The present invention could also encompass the so-called “brewing” process of beverage preparation—particularly for tea and coffee. Brewing involves the infusion over time of the ingredient in a fluid, most commonly hot water, whereas extraction or dissolution preparations produce a beverage within a few seconds.
For purposes of clarity, however, in this document the term “brewing” of an ingredient by a fluid is understood to encompass pressurized extraction of a powdered edible material (e.g. roast and ground powdered coffee), pressurized dissolution of edible soluble material (e.g. soluble tea, coffee, milk, or cocoa), or the infusion of an edible material in an infusion fluid under very low or atmospheric pressure, for a longer time than that required for extraction or dissolution (e.g. tea leaves in hot water).
The principle of extracting and/or dissolving the contents of a closed capsule under pressure is known and consists typically of confining the capsule in a receptacle of a machine, injecting a quantity of pressurized water into the capsule to extract or dissolve the substance, and then dispensing the resulting beverage from the capsule.
The injection is generally performed by piercing a face of the capsule with a piercing injection element, such as a fluid injection needle incorporated into the machine. Capsules applying this principle have already been described, for example in applicant's European patent no. EP 1 472 156 B1, and in EP 1 784 344 B1.
In addition, machines applying this principle have already been described for example in patents CH 605 293 and EP 242 556. According to these documents, the machine comprises a receptacle for the capsule, and a perforation and injection element made in the form of a hollow needle comprising in its distal region one or more liquid injection orifices. The needle has a dual function in that it simultaneously opens the top portion of the capsule while providing an inlet channel into the capsule for the injection of the water.
The machine further comprises a supply of the fluid (usually water) that is used to prepare the beverage from the ingredient(s) contained in the capsule. The machine further comprises a heating unit such as a boiler or a heat exchanger, which heats the water used therein to the working temperature. Finally, the machine comprises a pump for circulating the water from the tank to the capsule, optionally though the heating unit. The circulation of the water within the machine may be directed via a selecting valve means, such as for instance a peristaltic valve of the type described in applicant's European patent application EP 2162653 A1.
Such systems are particularly well-adapted to the preparation of coffee. One configuration for achieving this which is particularly advantageous is to provide a capsule containing roast and ground coffee powder, which is extracted with hot water injected therein.
Capsules have been developed for such an application, which are described and claimed in applicant's European patent EP 1 784 344 B1, or in European patent application EP 2 062 831.
In short, such capsules typically comprise:                a hollow body and an injection wall which are impermeable to liquids and to air, the wall being attached to the body and adapted to be punctured by e.g. an injection needle of the machine;        a chamber containing a bed of roast and ground coffee to be extracted;        an aluminium membrane disposed at the bottom end of the chamber for retaining the internal pressure therein, the membrane being associated with piercing means which create drainage holes in the aluminium membrane when the internal pressure inside the chamber reaches a certain pre-determined value; and        optionally, a deflection means configured to break up the jet of fluid, thereby reducing the speed of the jet of fluid injected into the capsule and evenly distributing the fluid across the bed of substance at a reduced speed.        
During extraction, the beverage capsule is pierced by the fluid injection needle of the beverage preparation machine, usually in the aluminium membrane. The liquid is injected in the capsule compartment and the pressure within the capsule increases, facilitating the extraction of the beverage from the ingredients contained within the capsule.
In some implementations, the beverage machine also pierces the capsule at a second location, for instance at its bottom, permitting the beverage to flow out during the operation of the machine. This therefore requires a second piercing means, appropriately disposed within the beverage machine so as to create a drain opening in the beverage capsule.
In others, the beverage capsule may be provided with an outlet, to which is generally affixed a valve or a membrane that opens when the pressure within the capsule builds up to the level required for proper beverage preparation. In one particular embodiment, the capsule is furnished with a plurality of projections. These projections are disposed within the capsule such that when the pressure within the capsule builds to a pre-determined point, the membrane will be deflected against the projections and rupture. The beverage may then flow past the projections to the outlet, usually through a plurality of channels provided among the projections for that purpose.
In WO 2010/137959, it is disclosed a system for preparing a predetermined quantity of beverage suitable for consumption using an extractable product. The system comprises an exchangeable capsule. The system further comprises an apparatus comprising a fluid dispensing device for supplying an amount of fluid, such as water, to the exchangeable capsule, a receptacle for holding the exchangeable capsule, and an outlet arrangement for supplying the beverage to a container, such as a cup. The capsule comprises a circumferential wall, a bottom, a lid, an entrance area and a closed exit area. The circumferential wall, the bottom and the lid enclose an inner space that comprises an extractable product. The system is arranged for bringing the fluid dispensing device in fluid connection with the entrance area for supplying the fluid to the extractable product for preparing the beverage. The system is further arranged so that, in use, the outlet arrangement is in fluid communication with the exit area for draining the prepared beverage from the capsule. The capsule further comprises a opening element that is arranged for providing an opening through the closed exit area for draining the prepared beverage from the capsule.
These arrangements are disadvantageous in that once the drain of the capsule is opened, it will remain so. If any liquid remains in the capsules after the brewing process is complete, it may leak from the drain when the capsule is removed from the beverage machine. This reduces the cleanliness and overall convenience of the machine.
Furthermore, when the membrane-and-projection system is used to provide the capsule drain opening, the channels which conduct the beverage past the projections may become clogged with undissolved clumps of beverage ingredient. The performance of the capsule and the quality of the beverage it produces is thus degraded.
It is accordingly an object of the invention to provide a means for opening a drain in a beverage capsule which ameliorates the above-mentioned deficiencies of the prior art.